Authorities in Washington state said Sunday that they're looking into whether an insane killer who escaped from a field trip organized by his mental hospital planned his getaway.

Police continued to search Sunday for Philip Arnold Paul, who escaped Thursday during a trip to a county fair.

Spokane County sheriff's spokesman Dave Reagan said the 47-year-old Paul left little clothing behind in his hospital room and carried a backpack and $50 on the outing.

Reagan said the trip to the fair, which included 30 other Eastern State Hospital patients, is an annual event that Paul easily could have anticipated.

Paul was committed after he was diagnosed as schizophrenic and acquitted by reason of insanity in the 1987 slaying of an elderly woman. He soaked her body in gasoline to throw off search dogs.